1. Field of the Invention
The present invention relates to a dry sump type lubricating device for an internal combustion engine.
2. Description of the Relevant Art
In accordance with the background art, a dry sump structure includes an oil tank separated from an engine. Oil, having been used for lubrication, is collected on a bottom of a case of the engine, and is pumped up by a scavenging pump to be returned again to the oil tank. The bottom of the case is partially recessed, at the sacrifice of the height of the engine, so that oil can be collected in the recessed bottom, and pumped up therefrom by the scavenging pump.
For example, Japanese Patent Laid-open No. Hei 4-298618 discloses a dry sump type lubricating device in which an oil tank is provided under a clutch in a crank case. Japanese Utility Model Publication No. Sho 56-54321 discloses a dry sump type lubricating device in which an oil pan is provided as an oil sump on the bottom of a crank case.
In the above-described background art, the lowest portion of the case must be further recessed for ensuring the pumping performance of the scavenging pump. Further, the pumping must be performed from the lower portion of the recess. This arrangement results in an overall height increase of the engine. Also, since the background art's lubricating devices use an oil pan, the number of parts is increased, and the weight and cost of the engine are increased. Further, a portion of the feed pump and scavenge pump are located on a tank side of the case, thereby enlarging the size of the case on the tank side and complicating the layout of the engine.